We need a stand-alone solution for screening all incoming corporate emails for attachments, cutting these attachments off and saving them on a web server for downloading. The downloads should be tracked for each recipient separately and statistic data saved to a database.
Basically the task is rather easy to understand: all attachments to the incoming (and only incoming) corporate emails should be removed from the messages, replaced with the unique URLs for every recepient, and then tracked, counting the events of downloads.
This should be an email proxy server solution, done as a plugin or module for existing open-source mail server. Similar solutions exist, but not quite serve the purpose.
If the existing solution will be found, finders fee will be paid.